There are various kinds of photosensitive compositions for use in the process for the production of lithographic printing plates, semiconductors such as IC, circuit boards for liquid crystal, thermal head, etc., or other photofabrication processes. For these purposes, photoresist photosensitive compositions are generally used. These photoresist photosensitive compositions are roughly divided into two types, i.e., positive-working and negative-working photoresist photosensitive compositions.
One of these positive-working photoresist photosensitive compositions is a chemically-sensitized resist composition as described in U.S. Pat. No. 4,491,628 and European Patent 249,139. The chemically-sensitized positive-working resist composition is a pattern-forming material which, when irradiated with radiation such as far ultraviolet rays, allows the exposed area to generate an acid in the presence of which it then undergoes reaction to change the solubility of the area irradiated with actinic radiation and the other area in a developer so that a pattern is formed on a substrate.
Examples of these pattern-forming materials include a combination of a compound which undergoes photodecomposition to generate an acid with acetal or 0, N-acetal compound (JP-A-48-89003 (The term "JP-A" as used herein means an "unexamined published Japanese patent application")), a combination of a compound which undergoes photodecomposition to generate an acid with orthoester or amide acetal compound (JP-A-51-120714), a combination of a compound which undergoes photodecomposition to generate an acid with a polymer having acetal or ketal in its main chain (JP-A-53-133429), a combination of a compound which undergoes photodecomposition to generate an acid with an enol ether compound (JP-A-55-12995), a combination of a compound which undergoes photodecomposition to generate an acid with an N-acyliminocarbonate compound (JP-A-55-126236), a combination of a compound which undergoes photodecomposition to generate an acid with a polymer having an orthoester group in its main chain (JP-A-56-17345), a combination of a compound which undergoes photodecomposition to generate an acid with a tertiary alkyl ester compound (JP-A-60-3625), a combination of a compound which undergoes photodecomposition to generate an acid with a silyl ester compound (JP-A-60-10247), and a combination of a compound which undergoes photodecomposition to generate an acid with a silyl ether compound (JP-A-60-37549, JP-A-60-121446). These compounds each exhibit a quantum yield of more than 1 in principle and thus show a high photosensitivity.
As a system which normally stays stable with time but undergoes decomposition to become alkali-soluble when heated in the presence of an acid there may be used a combination of a compound which generates an acid when exposed to light described in JP-A-59-45439, JP-A-60-3625, JP-A-229242, JP-A-63-27829, JP-A-63-36240, JP-A-63-250642, Poly. Eng. Sci., vol. 23, p. 1012 (1983), ACS. Sym. vol. 242, p. 11 (1984), Semiconductor World November 1987, p. 91, Macromolecules, vol. 21. p. 1475 (1988), SPIE, vol. 920, p. 42 (1988), etc. with a tertiary or secondary carbon (e.g., t-butyl, 2-cyclohexenyl) ester or ester carbonate compound. Such a system, too, has a high sensitivity and shows little absorption in far ultraviolet range. Thus, this system can be a system suitable for the reduction of wavelength of light from light source enabling ultrafine working.
The foregoing positive-working chemically-sensitized resists are roughly divided into two types, i.e., ternary system composed of an alkali-soluble resin, a compound which generates an acid when exposed to radiation (photo-acid generator) and a compound containing an acid-decomposable group which inhibits dissolution of the alkali-soluble resin and a binary system composed of a resin containing a group which undergoes reaction with an acid to undergo decomposition and become alkali-soluble and a photo-acid generator.
The foregoing binary or ternary positive-working chemically-sensitized resist is exposed to light to generate an acid from the photo-acid generator. In the presence of the acid thus generated, the positive-working chemically-sensitized resist is then subjected to heat treatment and development to provide a resist pattern.
JP-A-63-149640 proposes that an amine compound be added to stabilize the sensitivity of a lithographic printing plate which has been exposed. However, this proposal is disadvantageous in that the amine compound thus added causes the acid generated upon exposure to be partly deactivated, lowering the sensitivity of the lithographic printing plate. Further, EP-A-0795786 proposes that a specific photo-acid generator be used and 4-dimethylaminopyridine be used as an amine to inhibit the change in line width. However, this proposal is disadvantageous in that if the conventional amine compounds are added in an amount great enough to exert an effect of inhibiting the change in line width, sensitivity change can occur. This proposal also leaves something to be desired in resolution.